1. Field of the Invention
The present invention pertains generally to an article of manufacture which facilitates the application and sealing of sheet-like membrane roofing materials to the outside edges of buildings, more particularly, to a sheet metal mini-wall parapet which replaces prior art wood and/or masonry mini-wall parapets which are labor intensive and are relatively expensive to make and install. More particularly, the mini-wall parapet of this invention allows it to be substantially fully prefabricated of sheet metal such as galvanized steel, aluminum or stainless steel which is bent to form the finished product without the use of wood or masonry forming the bulk of the structure.
2. Discussion of the Background of the Invention
Roof edge sealing constructions referred to in the literature by several names such as mini-wall parapets, coping structures, roof edge assemblies, gravel stop assemblies, water dams, and the like, have been provided for the purposes of sealing the outer edges of construction components, anchoring sheet-like roofing or sealing membranes, retaining gravel ballasts, controlling water drainage, or for supporting facia members at the interfaces between various constructions and structures. For purposes of this disclosure, I will refer to these devices generally as mini-wall parapets. In the description of the drawings which follows, all elements in common with Prior Art FIG. 1 will include the same numbering system. Also, the dimensions of the various elements are not necessarily true to scale, but may be exaggerated in thickness or thinness to facilitate their disclosure.
Typically, as disclosed by prior art FIGS. 1(A-B), such an edge sealing mini-wall parapet 1 is fabricated on site at the edge of a roof by layering a plurality of wood planks (such as 2.times.6's or 2.times.8's) as shown. Such a wood plank mini-wall parapet 1 is typically formed from so-called pressure treated wood so that it is assured of moisture and insect resistance, but untreated wood can be utilized as well. The lowermost layer 3 of the wood plank mini-wall parapet is screwed to the roof deck 2 when the roof deck 2 is of wood or metal construction. If the deck 2 is of concrete or masonry construction, the lowermost layer is secured by anchor bolts or masonry fasteners 4. In both FIGS. 1(A-B), the edge of the roof deck 2 is shown over a typical outside wall which is composed of brick 19 and block 20. Each of the subsequent wood plank layers are nailed to the next lower layer by nails 5. The number of layered planks required is determined by the thickness of the insulation layer 6 on top of the roof deck 2. The height of the mini-wall parapet must be at least 3 1/2" higher than the height of the insulation layer as in FIG. 1(A). The roof membrane 7 is installed over the insulation layer 6, and usually laps over the top of the mini-wall parapet 1 as shown.
When the roof membrane 7 is formed from hot rubberized asphalt, it is usually applied directly to the roof deck 6 as shown in prior art FIG. 1B. Thus, when this technique is utilized, the insulation layer 6 is placed over the membrane 7 followed by a felt layer 8 and a layer of gravel 9. When this roofing system is employed, a ninety degree bend of the sheet membrane 7 is not permitted. Therefore, a 3".times.3" cant member 10 is nailed to the inside corner of the mini-wall parapet. This cant member 10 is formed from a 3".times.3" wood member which is sawed diagonally so that the upper and lower angles are only 45 degrees. Cant members 10 are also available pre-sawed from commercial roofing materials suppliers. When these cant members are employed, the height of the mini-wall parapet must be at least 3 1/2" above the top edge of the cant member 10.
The top surface 11 of the final layer of the mini-wall parapet must be tilted toward the surface of the roof as shown in each of the FIGS. 1(A-B). This tilt is provided to drain any moisture which accumulates along the top of the mini-wall parapet 1 toward the roof without allowing it to drip along the outside wall of the building.
The final tilted layer of the mini-wall parapet 1 can be formed in several ways. Any appropriate way is permissible provided that the upper surface 11 is sloped inwardly toward the roof surface at a slope of approximately 3/4" for an eight inch width. Thus, the upper surface 11 of the mini-wall parapet can be formed, for example, by a 2".times.8" plank milled to this slope as shown in prior art FIG. 1A, or the upper surface 11 can be tilted by shim 12 at its outside edge as shown in prior art FIG. 1B, so that the top surface 11 of the upper plank has this slope when nailed in place. The milled upper surface 11 is the preferred approach because the fit between the layers is maintained, but milled wood planks with such a slope are not commercially available so they must be milled by the installer. Clearly, this is labor intensive procedure for the installer. The shim technique is not as labor intensive, but it creates a void 13 between the layers and it causes the outside edges 14 of the upper layer 11 to be no longer perfectly square. These problems subject the final outer surface sheet metal coping member 15 of the mini-wall parapet to possible damage or denting in use because it does not fit snugly around the upper surface of the mini-wall parapet 1.
After the wood plank portion of the prior art mini-wall parapet of FIGS. 1(A-B) is installed, an elongated cleat 16 of sheet metal is nailed or screwed at 17 laterally along the length of the outside wall of the mini-wall parapet 1. If desired for a tighter fit of the coping 15, a similar cleat may also be installed along the inside wall of the mini-wall parapet as disclosed in several of the prior art patents identified in the INFORMATION DISCLOSURE STATEMENT, which is hereby incorporated by reference.
The bottom edge of the cleat 16 is bent outward slightly as shown in prior art FIGS. 1(A-B) so that the outer finishing cap or coping member 15 of sheet metal can be installed over the whole mini-wall parapet. The cleat extends down past the interface 18 between the deck and the lower layer of the mini-wall parapet so that the coping member 15, when installed, covers and protects the interface 18 between the mini-wall parapet and the roof deck. The coping member 15 is prefabricated by bending sheet metal in the shape shown. The coping member 15 includes an upperly bent flange (unlabelled as shown) which fits snugly behind the cleat 16 when installed. The coping member 15 is installed by wedging this upwardly bent flange behind the bottom edge of the cleat member, and stretching the top of the coping member over the top of the mini-parapet 1 as indicated by the dotted structure in prior art FIG. 1A. The coping member 15 and the cleat 16 are sufficiently flexible so that they can be elastically deformed when the coping is stretched over the top of the mini-wall parapet (shown dotted in FIG. 1A) without exceeding the elastic limit of any of the bends in the coping or the cleat. Thus, when installed, the coping 15 snaps snugly and permanently over the top of the mini-wall parapet and tightly covers all of the mini-wall parapet material and the sealed edge of the roof membrane 7 underneath the coping. Therefore, the mini-wall parapet and the sealed edge of the roof membrane are fully protected from weather and moisture. The coping structure 15 of prior art FIG. 1B is installed in the same manner.